1. Field of the Invention
The present invention is related to improvements on exhaust pipes; in particular, to a gas-liquid separation system and a method for gas-liquid separation, for preventing reactions of exhaust gas and waste liquid that may cause pipe congestion due to crystallization.
2. Description of Related Art
The exhaust gas and waste water released from current semiconductor processes are of acidity or alkalinity. For a general oven-pipe process (e.g. low-pressure chemical vapor deposition process; LPCVD process), during the process, the semiconductor substrate is placed in a LPCVD machinery for execution of required reactions, allowing a thin film to form there on the semiconductor substrate.
NH4Cl by-product is generated in a process of wet oxidation of silicon and nitride for forming a thin layer of silicon nitride on a semiconductor substrate in a LPCVD machinery, which NH4Cl being generated in the form of vapor and exhausted through the LPCVD machinery (as shown); however, when upon exhaustion of such a NH4Cl by-product to a pipe 1a (as shown in FIG. 1), wherein the arrow of dotted line indicates gas and the arrow of solid line indicates liquid, since the temperature of the pipe 1a is lower than the NH4Cl, thus liquid may be formed therein from vapor; furthermore the pipe 1a is not constructed in the form of a straight line, but having multiple turns 2a. As a result, the aforementioned two factors may let NH4Cl crystallize inside these turns 2a of the pipe 1a, resulting in jamming of NH4Cl crystals in the pipe 1a (as shown in FIGS. 2 and 3), which makes NH4Cl fail to be successfully exhausted and causes pressure surge due to reduced space, thus negatively affecting the control over entire process pressure and leading to machinery shutdown. In order to re-run the machinery (not shown), engineers need to dissemble the pipe 1a to remove the NH4Cl crystals, thus significantly consuming valuable cost and time which is becoming a critical issue required to be addressed.
Accordingly, the inventors of the present invention have considered the above-mentioned improvable defects, and, based on long-term professional experiences, together with thorough researches and observations, in conjunction with applications of fundamental theories, thus proposed the present invention having reasonable design and effectiveness in amelioration of the aforementioned disadvantages.